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The paper addresses the model reduction problem for linear and nonlinear systems using the notion of least squares moment matching. For linear systems, the main idea is to approximate a transfer function by ensuring that the interpolation…

Optimization and Control · Mathematics 2021-10-13 Alberto Padoan

Many empirical studies suggest that samples of continuous-time signals taken at locations randomly deviated from an equispaced grid (i.e., off-the-grid) can benefit signal acquisition, e.g., undersampling and anti-aliasing. However,…

Information Theory · Computer Science 2025-09-10 Oscar López , Özgür Yılmaz

Computational methods for sensitivity analysis are invaluable tools for scientists and engineers investigating a wide range of physical phenomena. However, many of these methods fail when applied to chaotic systems, such as the…

Chaotic Dynamics · Physics 2015-06-16 Patrick J. Blonigan , Qiqi Wang

The aim of this paper is two-fold: firstly, to present subspace embedding properties for $s$-hashing sketching matrices, with $s\geq 1$, that are optimal in the projection dimension $m$ of the sketch, namely, $m=\mathcal{O}(d)$, where $d$…

Numerical Analysis · Mathematics 2021-05-26 Coralia Cartis , Jan Fiala , Zhen Shao

Full-waveform inversion (FWI) is a widely used technique in seismic processing to produce high resolution Earth models that fully explain the recorded seismic data. FWI is a local optimisation problem which aims to minimise in a…

Geophysics · Physics 2019-11-22 Christopher Zerafa , Pauline Galea , Cristiana Sebu

This paper introduces DRANet-SWD as a novel complete pipeline for disentangling content and style representations of images for unsupervised domain adaptation (UDA). The approach builds upon DRANet by incorporating the sliced Wasserstein…

Computer Vision and Pattern Recognition · Computer Science 2026-02-03 Joel Sol , Shadi Alijani , Homayoun Najjaran

Variational data assimilation is a technique for combining measured data with dynamical models. It is a key component of Earth system state estimation and is commonly used in weather and ocean forecasting. The approach involves a…

Numerical Analysis · Mathematics 2026-04-30 I. Daužickaitė , M. A. Freitag , S. Gürol , A. S. Lawless , A. Ramage , J. A. Scott , J. M. Tabeart

In the light of the fact that the stochastic gradient descent (SGD) often finds a flat minimum valley in the training loss, we propose a novel directional pruning method which searches for a sparse minimizer in or close to that flat region.…

Machine Learning · Computer Science 2020-10-15 Shih-Kang Chao , Zhanyu Wang , Yue Xing , Guang Cheng

Mode connectivity is a recently introduced frame- work that empirically establishes the connected- ness of minima by finding a high accuracy curve between two independently trained models. To investigate the limits of this setup, we examine…

Machine Learning · Computer Science 2018-06-20 Akhilesh Gotmare , Nitish Shirish Keskar , Caiming Xiong , Richard Socher

Incorporating prior knowledge on model unknowns of interest is essential when dealing with ill-posed inverse problems due to the nonuniqueness of the solution and data noise. Unfortunately, it is not trivial to fully describe our priors in…

Geophysics · Physics 2021-06-24 Ali Siahkoohi , Gabrio Rizzuti , Felix J. Herrmann

Online learning algorithms require to often recompute least squares regression estimates of parameters. We study improving the computational complexity of such algorithms by using stochastic gradient descent (SGD) type schemes in place of…

Machine Learning · Computer Science 2014-11-21 Nathaniel Korda , Prashanth L. A. , Rémi Munos

Inversion techniques are widely used to reconstruct subsurface physical properties (e.g., velocity, conductivity) from surface-based geophysical measurements (e.g., seismic, electric/magnetic (EM) data). The problems are governed by partial…

Machine Learning · Computer Science 2022-06-17 Yinan Feng , Yinpeng Chen , Shihang Feng , Peng Jin , Zicheng Liu , Youzuo Lin

4D seismic imaging has been widely used in CO$_2$ sequestration projects to monitor the fluid flow in the volumetric subsurface region that is not sampled by wells. Ideally, real-time monitoring and near-future forecasting would provide…

Geophysics · Physics 2021-12-07 Shihang Feng , Xitong Zhang , Brendt Wohlberg , Neill Symons , Youzuo Lin

In this work we address the subspace recovery problem. Given a set of data samples (vectors) approximately drawn from a union of multiple subspaces, our goal is to segment the samples into their respective subspaces and correct the possible…

Information Theory · Computer Science 2013-01-29 Guangcan Liu , Zhouchen Lin , Shuicheng Yan , Ju Sun , Yong Yu , Yi Ma

Reliable quantitative analysis in scanning (transmission) electron microscopy (S(T)EM) is often hindered by image drift during long-duration spectral mapping for elemental analysis or for various material functions. We here present…

Instrumentation and Detectors · Physics 2026-04-22 Zac Thollar , Kanto Maeda , Tetsuya Kubota , Taka-aki Yano , Qiwen Tan , Takumi Sannomiya

Iterative least-squares MR reconstructions typically use the Conjugate Gradient algorithm, despite known numerical issues. This paper demonstrates that the more recent LSMR algorithm has favourable numerical properties, and is to be…

Medical Physics · Physics 2022-12-14 Tobias C Wood

We introduce sliced optimal transport dataset distance (s-OTDD), a model-agnostic, embedding-agnostic approach for dataset comparison that requires no training, is robust to variations in the number of classes, and can handle disjoint label…

Machine Learning · Computer Science 2025-05-16 Khai Nguyen , Hai Nguyen , Tuan Pham , Nhat Ho

We propose a new algorithm for the problem of recovering data that adheres to multiple, heterogeneous low-dimensional structures from linear observations. Focusing on data matrices that are simultaneously row-sparse and low-rank, we propose…

Machine Learning · Computer Science 2024-01-19 Christian Kümmerle , Johannes Maly

Many computer vision problems (e.g., camera calibration, image alignment, structure from motion) are solved with nonlinear optimization methods. It is generally accepted that second order descent methods are the most robust, fast, and…

Computer Vision and Pattern Recognition · Computer Science 2014-05-06 Xuehan Xiong , Fernando De la Torre

Classical shadows (CS) offer a resource-efficient means to estimate quantum observables, circumventing the need for exhaustive state tomography. Here, we clarify and explore the connection between CS techniques and least squares (LS) and…

Quantum Physics · Physics 2024-12-11 Zhihui Zhu , Joseph M. Lukens , Brian T. Kirby